Hinge and stop provisions for hand



Feb. 21, 1956 C. W. HART HINGE AND STOP PROVISIONS FOR HAND OPERATEDIMPLEMENTS OR TOOLS Filed Jan. 7, 1953 H G. 5. 12 i- 2725 6 20 30 3/ 334 32 7 ,QD n, z'sww My! 2/ gvgw I7, l0 25 27 5 MM 4.: I 71] I/vvE vToR.v 34 amaa: x4 A fl Ff BY ATTORNEYS United States Patent HINGE AND STOPPROVISIONS FOR HAND OPERATED IMPLEMENTS OR TOOLS Claude W. Hart,

Manufacturing of Indiana Seymour, Ind., assignor to Seymour Company,Seymour, Ind., a corporation This invention relates to improvements inhinge and stop provisions for hand operated implements or tools, andmore particularly to an improved hinge assembly embodying a novelarrangement of stop elements for use on certain two-handled, bladed handtools, such as post hole diggers and the like.

For brevity of present description the specification and claims hereinare largely directed to a post hole digger of clam or clam shell type,as distinguished from post hole angers, the latter usually having asingle rotatable handle with part-helical blades subject to rotarymotion for engaging the blades with the earth. Post hole diggers, indistinction, are operated by forcible insertion of a pair of opposedcupped blades into the earth in the location of the hole with handlestogether, followed by divergence of the handles resulting in convergenceof the blades, followed by removal of the earth by direct lifting actionof the divergent handles. It is more particularly to the latter type oftools or implements, that the present improvements are directed.

It has heretofore been conventional to construct post hole diggers of apair of handled blades, and providing the assembly with a yoke structurehaving bolt apertures, with a pivot pin or bolt extending through suchapertures, or alternately, to provide inturned ears on the blades, withbolt holes through the blade cars, a bolt or pin being directed throughsuch apertures as a pivot. Either of these older types is distinctlydisadvantageous in that the yoke entails separate expensive elements,and in case the blades themselves carry the pivot bolt apertures, thegauge of metal usually employed in the blades is such as to make forshort life of the apertured blade portions, sometimes with a severecutting action on the pivot bolt, resulting in a considerable wobble orlooseness in the pivot region due to wear even after only a short periodof service. Furthermore, the need for apertured extensions of the bladessolely for purposes of pivoting the companion cooperating parts of thedigger, needlessly enhances the cost of cutting and forming tools forproduction of the blades, and involves, a considerable waste of metal ofthe blade. It is accordingly a principal and major object of the presentimprovements to reduce the costs of producing the blades of implementsof the kind in discussion; to provide a simple, rugged, and much longerlived pivot assembly, with a substantial reduction in cost and a longeruseful life of the tool with minimum requirements of service attentionthereto.

An additional object of importance consists in the provision of a novelstop arm or arms, located at a distance from the hinge assembly, andembodying a provision for maintaining the handle blades in parallelismbetween periods of active use or at the end of each working stroke ofthe tool, at the same time serving to relieve the hinge pin or pivot oftwisting or cocking stresses.

Yet another and valuable object of the invention is realized in a hingeassembly for the general purpose noted, which provides an augmentedbearing area beparts of the hinge proper, thereby reducing unitpressures on the pin when under load.

Of great importance as an objective of the current improvements is theprovision of a novel stop and hinge assembly consisting of companioncooperating parts constituting both a hinge structure and a stop orabutment, establishing a limit of inward or convergent movement of thehandles, it being noted that the two part stop and hinge assembly issusceptible of usage in a variety of twohandled, usually manuallyoperated, implements or tools.

The foregoing and numerous other objects and advantages of the inventionwill more clearly appear from the following detailed description of apost hole digger equipped with the present improvements, particularlywhen the description is considered in connection with the accompanyingdrawing, in which:

Fig. 1 is a side elevatonal view of a embodying the presentimprovements;

Fig. 2 is an elevational view taken at a right angle to that of Fig. 1;

Fig. 3 is a view generally similar to Fig. 1, but showing the operativemetal parts of a post hole digger together with lower portions of thehandles, in section, as viewed along line 33 of Fig. 2;

Fig. 4 is a transverse sectional view, partly in elevation, as takenalong line 44 of Fig. l, and

Fig. 5 is a transverse sectional view in a plane including the pivotaxis, and located by line 55 of Fig. 1. In each of Figs. 1-3, thehandles are foreshortened somewhat to enable showing the operative metalparts on a somewhat larger scale.

Referring now by characters of reference to the drawing, there is shownby way of illustrative example a post hole digger the general type ofwhich is well known as characterized by a clam shell action, andincluding a pair of elongate, usually hardwood handles 10 and 11, and apair of hollow scoop-like blades 12 and 13 respectively attached to thehandles 10 and 11, in a manner later to be described. Each of the bladesis extended upwardly of the blade body to form an attachment portion orsocket, as indicated at 14. In the socket-forming region, the metal ofthe blades is folded or bent to constitute a pair of parallel flanges 15and 16 which result in an openside socket, receiving a squared lower end17 of the connected handle. Thus the two sockets as assembled to thehandles, have their single open sides presented toward each other.Connection of each blade to its operating handle 10 or 11, is made as bya pair or other desired number of assembly bolts 20 extendedtransversely of the socket and the handle, and provided with externalnuts 21 as shown.

Serving as a closure for the open side of each of the handle sockets, isone of a companion pair of members collectively constituting a stop andhinge assembly providing for the operative pivotal connection betweenthe two handled blades of the assembly.

Referring now more particularly to the parts of the stop and hingestructure, it will usually be preferred for reasons of economy, toconstitute the companion hinge sections of identical or substantiallyidentical parts, thus conducing to economy in die and tooling costs. Inthe example shown, each hinge part includes a substantially flat baseplate 25. This is shown as provided with squared apertures of a size forthe reception of the squared upper shank portion 26 of each of the bolts20 when the latter are of carriage type. At one, shown as the lower, endof each of the stop-hinge parts, are a pair of cars or projections 27.If the stop-hinge elements are of suflicient gauge or thickness, asingle such car on each part will sutfice, but it is preferred forbetter rigidity and spacing of pivot zones, to provide a pair of suchears 27 in overlapped relation as best shown by Fig. 5, each tween thepin and other post hole digger of the ears 27 being apertured for thereception of a pivot pin exemplified by bolt 30 extending through theapertures therefor, which obviously, in assembly, are all in register.The pivot bolt is provided with a nut 31.

It is greatly preferred for better pivoting action and longer life ofthe pivot or hinge elements, to utilize metal in the stop-hingestructure, which is of considerably greater weight or gauge than isprovided in the blades 12-13. Furthermore, by the provision of stophingeelements formed entirely separately from the blades, or independently ofthe yokes sometimes employed in the pivot region of post hole diggers, awider choice of materials is possible, as well as certain economies informing.

The apertured pivot ears 27 of each hinge assembly part, are shown aspreferred, at one or the lower end of each of the base plates.Preferably spaced substantially from the pivot ears and at the oppositeor uppermost end of the base plate, is a right angle flange turnedinwardly of the base plate toward the opposite handle, and indicated at32, and constituting as will appear, a stop arm serving to limit theextent of approaching movement of the handles toward each other, whenopening the blades 12-13 to the maximum extent, prior to loading theblades.

It is a preference so to form and proportion the apertured ears 27 inrelation to the stop arms 32 on the companion parts of the hinge andstop assembly, that the effective spacing between the plates realized bythe apertured cars 26, is identical with the spacing which results frommutual engagement of the paired stop arms 32. With this relation ofparts, when the handles are brought together as closely as possible,with the blades fully open as shown by Fig. 1, the base plates 25 areparallel, as are the handles, with assured spacing therebetween at alltimes, thus avoiding any possible impact between the handles and thehands of the operator. It will also be noted as desirable to form up thestop arms so that each is at a right angle to the ears 27 of the samefixture.

It will have appeared that the spacing of the stop arms 32 at asubstantial distance away from the operative axis of the implement,being in this case the axis of bolt 30, greatly decreases the unitpressures and impact effects on the mating edges of the arms when sameare brought together. Such unit pressures are still further minimized bythe provision, best appearing in Fig. 4, of a prominent saw-tooth edgeon the free margin of each of the stop arms. By reason of this formationthere results a series of tongues on the end of each stop arm, andconforming tongue-receiving recesses on the region of the companion stoparm. Thus when so constructed, the tongues such as 33 will interfitcorresponding recesses such as 34 of the companion stop arm. In case thepivot bolt should become bent slightly, the interengagement of thetongues and recesses will tend to cam the parts into parallelism whenthe handles are brought together.

Although the hinge and stop assembly would be similarly operative ifonly a single stop arm were utilized, the length of which wouldcorrespond to the spacing of the plates at their pivoted end with bladesopen, it is nevertheless preferred to utilize a pair of the arms 32,substantially as shown by Fig. 4 and others.

t will have appeared that when the handles are convergingly actuated andbrought as closely as possible together with the stop arms ininterfitted relation as shown, this formation of the stop arms, asduring periods of haulage, storage or otherwise between periods ofusage, maintains the arms in accurate parallelism and relieves the pivotbolt of any cocking or twisting stresses.

A number of advantages result from the utilization of the separatestop-hinge assembly as described, in comparison of this arrangement witholder aind conventional constructions. In addition to the markedreduction in blade tooling costs, it enables the use of a much heaviermaterial, as above noted, in the stop and hinge assembly. Similarly, theuse of the rigid longitudinal plate 25 as a cover over the otherwiseopen side of the blade socket, results in substantially a completeembracing relation of the socket to the lower end of the handle, thustending to obviate wear of the bolts in the bolt passages through thehandles, permitting a much tighter takeup of the nuts 21 without drawingthe bolts into the wood handles, and likewise providing a rugged, rigidU-shaped bridge between the paired handle and blade assemblies, in thepivot zone.

It will have been observed that no additional attachment bolts arerequired incident to the usage of the improved stop and hinge assemblydescribed, inasmuch as the companion hinge sections or fittings aresecured in place, substantially in vertical registry, by the same bolts29 as are utilized for attachment of the blades to the handles.

Although for convenience and brevity of description the improvedstop-hinge assembly has been described as designed for and applied to areciprocating-handle type of post hole digger, the same fittings, withor without minor modification, may be applied to certain othertwo-handled bladed tools, for example, hedge clippers and otherimplements which are operated by similar reciprocal movement of thehandles in opposite directions.

Although the invention has been described by particularized reference toa selected commercial embodiment, the detail of description should beunderstood solely in an illustrative, rather than in any limiting sense,numerous variants being possible within the fair scope of the claimshereunto appended.

I claim as my invention:

1. A combined stop and pivot assembly for a post hole digger having apair of handles, and a hollow blade carried by the lower end of eachhandle, the pivot assembly comprised of two companion coacting parts,each such part including a base attached to an inside face portion ofone handle near its lower end, a pair of apertured pivot ears carried byand projected outwardly of the base toward the opposite handle, the twoparts of the pivot assembly being vertically in register, with the pivotears of one of said parts laterally adjacent corresponding ears of thecompanion part, and with the apertures of the ears in register, a pivotpin common to and extended through the several ear apertures, and stoparms carried by the respective said parts of the pivot assembly inpositions to abut each other above said pivot pin upon extremeapproaching movement of the handles, and serving thereby to limit thehandle spacing in one position of the relatively movable parts, saidstop arms being located at an appreciable distance upwardly of thehandles, in respect to the pivot pin.

2. A combined stop and pivot assembly for a hand implement such as apost hole digger having a pair of handles, and a pair of opposed hollowblades, one attached to the lower end of each handle, the pivot assemblycomprised of two parts which coact to constitute a hinge between thehandled blades, each of the two parts of the pivot assembly including asubstantially flat base attached to the inside surface portion of alower end of one handle, a pair of apertured pivot ears projecting in adirection away from the base and the handle by which it is carried, thepivot ears of one said part overlapping the corresponding ears of thecompanion part, with the ear apertures in register, a pivot pin extendedthrough the several ear apertures, a stop arm constituted as a rightangled, inturned projection of each of the bases of the pivot assemblyand arranged to abut each other above said pivot pin when the blades areopen, the abutting stop arm portions being provided with cooperatingtongues and recesses for mutually interfitting relation when the bladesare fully opened, whereby to keep the handles and blades in parallelism,and to relieve the pivot pin of cocking or twisting tendencies, the saidparts of the pivot assembly consisting of elements separate from theblades and handles.

3. A combined stop and hinge assembly for a twohandled, bladed tool inwhich each handled blade is pivotally related to the other, the assemblyconsisting of a pair of coacting metal hinge elements each including abase plate, paired, spaced, apertured ears projected marginally from andlntegral with the base plate, the base plate being apertured formounting members such as bolts or rivets, and a stop arm on each baseplate at a distance from the apertured ears, and a hinge pin extendingas a pivot through the several apertures, the stop arms being providedwith interfitted portions for interfitting laterallyaligning engagementabove said hinge pin when brought together.

4. The combination and arrangement of elements in a combined stop andhinge assembly substantially as recited by claim 3, but furthercharacterized by the pro vision of an outwardly convergent tongue at thefree end of one stop arm and a compatible tongue-receiving recess in theregion of the free end of the opposite stop arm, the tongue and recessbeing proportioned for reception of the tongue in the recess when thestop arms are brought together.

5. As an article of manufacture, a combined stop and hinge assembly forthe paired handled blades of a post hole digger, said assemblyconsisting of two hinge elements, each said hinge element comprising anelongate base plate provided with longitudinally spaced bolt apertures,the base plates being adapted for longitudinal of the base plate, theend of each base plate opposite the pivot ears being turned outwardly ofthe base plate at a right angle thereto, whereby to provide a rigid stoparm spaced substantially away from the region of the pivot ears, a boltextended through the several apertures of the pivot ears to provide ahinge pin between the base plates and parts connected thereto, the freemarginal portions of the stop projections of the base plates beingprovided with a series of deep reentrant portions constituting openrecesses, with projecting teeth intervening said recesses, and with theteeth and recesses of the cooperating stop arms adapted for mutualinterfitting abutment above said pivot bolt when the stop arms arebrought together, the aggregate length of the stop arms beingsubstantially equal to the aggregate distance from the centers of theapertures of the ears, to the respective base plates, whereby inassembly, the stop arms together with the pivot ears and pivot bolt,coact to maintain the handles of a tool in substantial parallelism whenthe handles are brought to full convergence.

References Cited in the file of this patent UNITED STATES PATENTS

